Figure 1From: Should we reconsider the routine use of placebo controls in clinical research? Response curves for hypothetical clinical trials of a novel medication for insomnia (higher outcome scores represent more severe sleep problems). (a) three-arm trial with usual-care, placebo, and active-treatment groups; (b) two-arm trial with placebo and active-treatment groups; (c) two-arm trial with usual-care and active-treatment groups.Back to article page